Manufacture of plate-glass.



No. 734,125. v PATENTED JULY 21, 1903.v

A. M. Gow.

MANUFAGTURE o11 PLATE GLASS. APPLICATION funn 11017.12, 1902.

I0 MODEL.

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. vUNITEin STATES Patented July 21, 1903.

PATENT OFFICE.

ALEXANDER M.

GOW, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGNMENTS, OF ONE-HALF TO ST. LOUIS PLATE GLASS COMPANY, OF VALLEYPARK, MISSOURI, A CORPORATION OF MISSOURI.

MANUFACTURE'OF- PLATE-GLASS.

SPECIFICATION forming part of Letters Patent N o. 734,125, dated July 21, 1903. Application filed November 12, 1902. Serial No 131,009. (No model) T a/ZZ whom, t may concern:

Be it known that I, ALEXANDER M. Gow,

of Pittsburg, Allegheny county, Pennsylvania, have invented a new and useful Improvement in the Manufacture of Plate-Glass, of

which the following is a full, clear, and exact description, reference being had to the accompanying drawings, in which- Figure l is a sectional longitudinal elevaro tion showing apparatus'constructed for carrying out my invention; and Fig. 2 is a partial vertical cross-section, on a larger scale, in the rear of the roller.

My invention relates to the manufacture of I5 plate-glass by rolling, and is designed to reduce lthe amount of grinding necessary by enabling a thinner plate to be made and to reduce the irregularities on the surface of the glass and the amount of contained airbub 2o bles.

Heretofore in rolling glass it has been teemed upon a metal table and then rolled by a heavy roller supported upon side strips Whose thickness determines the thickness of the rolled sheets. With this system the chilling action between the table and the roller produces an uneven surface on the glass and air is 'entrained, which appears in the form of small bubbles near the surface of the glass.

3o For these reasons it has been necessary to grind oif both sides ofthe rolled plate to a sufficient depth to remove the irregularities and air-bubbles, and to produce a finished plate of oue-quarter-inch thickness it has been 3 5 necessary to roll a plate approximately sevensixteenths of an inch thick. My invention largely overcomes this difficulty, enables a thinner sheet to be rolled or one nearer the thickness of the final sheet, and, furthermore,

4o gives the upper side of the plate neXt the roller,v

a fire-polished surface.

The invention consists in passinga current of electricity through the glass from the table tothe roller, or vice versa, thereby melting 4,5 the successive portions of the glass as the roller passes along the table. Itis well known that as glass is heated its conductivity increases and that molten glass is a conductor of electricity, and I utilize this characteristic `and 12.

to impart a better surface to the sheet during 5o rolling.

In the drawings, in which I show one form of apparatus for carrying out my invention, 2 represents a table, whose legs 3 rest upon insulators 4. The table is shown as being hollow and water-cooled by inlet and outlet pipes and 6 at opposite ends, so that a wa- `ter circulation may be kept up during the rolling. The side strips 7, which support the roller 8, are shown as of metal and insulated 6o from the table by insulating-strips 9, which extend throughout their length. I have shown the roller as provided with an annular watercooling space lO, which connects with the trunnions, so that the water passes in at one `trunnion and out through the other during the rolling. One terminal l1 is shown as connected to the upper portion of the table, while the other terminal l2 leads to brushes-13, resting upon the surface of the roller. These 7o wires preferably lead from the terminals of a transformer which provides, preferably, an alternating current of low voltage and large amperage.

In using the vapparatus 'glass is teemed 75 upon the table in the usual manner andthe roller is moved along, the current at the same time being cut in through thewires l1 As the roller proceeds the current 0f electricity will flow between the table and 8o the roller through that -portion of the glass Vbetween them and possibly through the adjacent portions. In this portion of the glass which at any moment is between the roller and the table a high degree of heat will be generated in proportion to the amount of current flowing through, and it will therefore be raised to a higher temperature and melted, being hotter than the glass in front of and behind the roller. The width of this 9o heated portion of glass will depend on the quantity of current passing. Asthe roller moves forward these successive molten portions of glass are exposed vto the cooling action of the air, thus giving on the topsurface a fire-nish. v

The advantages of the invention result from passing currents of electricity between l[he table and roller, or vice versa, since thereby the air-bubbles are reduced and a better surface is imparted. The labor and expense of grinding are therefore greatly reduced.

The insulatingsupports for the roller may be dispensed with by supporting the roller over and independent; of the table, and in such case the roller can be adjusted downwardly and passed hack and forth over the same plate to vremove irregularities which might result from a single rolling. The water-cooling may be used or not, as desired, though I prefer it in order to prevent excessive heating of the table and roller as their successive portions are subjected to the action of the electrical current.

Two or more rollers may be used instead of a roller and table, and many other Variations may be made in the form and arrange ment of the apparatus Without departing from my invention, since I consider myself the first to heat the glass being rolled by passing a current through the successive portions in contact With the roller.

I claim- 1. The method of forming plate or sheet glass consisting in rolling glass into a plate or sheet, and passing a current of electricity through the successive portions during rolling; substantially as described.

2. The method of making plate or sheet glass, consistingin rolling the same and passing a current of electricity through the successive portions of the glass between the forming surfaces during the rolling operation; substantially as described.

3. The method of forming sheet or plate glass, consisting in passing an alternating current of low voltage and high amperage through the successive portions of the glass between the forming surfaces during rolling; substantially as described.

In testimony whereof I have hereunto set my hand.

ALEXANDER IWI. GOW.

Witnesses:

L. M. REDMAN, H. M. CORWIN. 

